Fatigue brought on by malfunction of the central and peripheral nervous systems

Abstract:

Increased fatigability necessarily occurs in every patient with muscle weakness, regardless of whether the latter is due to a central or peripheral neurological disorder. The tendency for disuse to increase fatigability, as a secondary phenomenon, must also be considered; disuse affects both motoneuron recruitment and the biochemical and physiological properties of the muscle fibers. In recent studies impaired recruitment has been observed in postpolio patients, while patients with multiple sclerosis or spinal cord injury have shown, in addition, altered neuromuscular function. Findings are also presented in ALS and the chronic fatigue syndrome. In general, the most dramatic increases in fatigability take place in disorders of the peripheral nervous system and almost any cell component can be incriminated. There is a need to study fatigability systematically in neurology and rehabilitation.

 

Source: McComas AJ, Miller RG, Gandevia SC. Fatigue brought on by malfunction of the central and peripheral nervous systems. Adv Exp Med Biol. 1995;384:495-512. http://www.ncbi.nlm.nih.gov/pubmed/8585475

 

Serum levels of carnitine in chronic fatigue syndrome: clinical correlates

Abstract:

Carnitine is essential for mitochondrial energy production. Disturbance in mitochondrial function may contribute to or cause the fatigue seen in chronic fatigue syndrome (CFS) patients. One previous investigation has reported decreased acylcarnitine levels in 38 CFS patients.

We investigated 35 CFS patients (27 females and 8 males); our results indicate that CFS patients have statistically significantly lower serum total carnitine, free carnitine and acylcarnitine levels, not only lower acylcarnitine levels as previously reported. We also found a statistically significant correlation between serum levels of total and free carnitine and clinical symptomatology. Higher serum carnitine levels correlated with better functional capacity.

These findings may be indicative of mitochondrial dysfunction, which may contribute to or cause symptoms of fatigue in CFS patients.

 

Source: Plioplys AV, Plioplys S. Serum levels of carnitine in chronic fatigue syndrome: clinical correlates. Neuropsychobiology. 1995;32(3):132-8. http://www.ncbi.nlm.nih.gov/pubmed/8544970

 

Neuropsychological impairments in chronic fatigue syndrome, multiple sclerosis, and depression

Abstract:

To examine the degree and nature of cognitive impairments in chronic fatigue syndrome, a comprehensive neuropsychological battery was given to patients with chronic fatigue syndrome, multiple sclerosis, depressed patients, and healthy controls. The battery included tests of attention and concentration, information processing speed, verbal and visual memory, intellectual ability, and concept formation. Measures of depression and anxiety were also obtained.

The chronic fatigue syndrome group did not differ from the depressed group in overall neuropsychological performance, but differed from the multiple sclerosis and control groups. The most significant impairment was in information processing speed in the chronic fatigue syndrome group. Depression and anxiety were not related to neuropsychological performance. The influence of reduced information processing on other areas of cognition is discussed.

 

Source: DeLuca J, Johnson SK, Beldowicz D, Natelson BH. Neuropsychological impairments in chronic fatigue syndrome, multiple sclerosis, and depression. J Neurol Neurosurg Psychiatry. 1995 Jan;58(1):38-43. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1073266/ (Full article)

 

Sleep, neuroimmune and neuroendocrine functions in fibromyalgia and chronic fatigue syndrome

Abstract:

The justification for disordered chronobiology for fibromyalgia and chronic fatigue syndrome (CFS) is based on the following evidence: The studies on disordered sleep physiology and the symptoms of fibromyalgia and CFS; the experimental studies that draw a link between interleukin-1 (IL-1), immune-neuroendocrine-thermal systems and the sleep-wake cycle; studies and preliminary data of the inter-relationships of sleep-wakefulness, IL-1, and aspects of peripheral immune and neuroendocrine functions in healthy men and in women during differing phases of the menstrual cycle; and the observations of alterations in the immune-neuroendocrine functions of patients with fibromyalgia and CFS (Moldofsky, 1993b, d). Time series analyses of measures of the circadian pattern of the sleep-wake behavioural system, immune, neuroendocrine and temperature functions in patients with fibromyalgia and CFS should determine whether alterations of aspects of the neuro-immune-endocrine systems that accompany disordered sleep physiology result in nonrestorative sleep, pain, fatigue, cognitive and mood symptoms in patients with fibromyalgia and CFS.

 

Source: Moldofsky H. Sleep, neuroimmune and neuroendocrine functions in fibromyalgia and chronic fatigue syndrome. Adv Neuroimmunol. 1995;5(1):39-56. http://www.ncbi.nlm.nih.gov/pubmed/7795892

 

Vestibular function test anomalies in patients with chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is distinguished by the new onset of debilitating fatigue that lasts at least 6 months, concomitant with other symptoms to be described later. Many CFS patients complain of disequilibrium, yet the exact type of the balance dysfunction and its function and its location (peripheral vs. central) have not been described.

Herein we report results of vestibular function testing performed on 11 CFS patients. These results revealed no predominant pattern of abnormalities. Patients typically performed below average in dynamic posturography testing, with a significant number of falls in the tests requiring subjects to depend heavily on the vestibular system. One patient had abnormal caloric testing, while 3 had abnormally low earth vertical axis rotation (EVA) gains at the higher frequencies tested.

As a group, the average gain of EVA was significantly lower than normals in the 0.1 – 1.0 Hz range (p < 0.05). In earth horizontal axis rotation, the CFS group had a higher than normal bias value for the optokinetic (OKN) and eyes open in the dark conditions (p < 0.05), but had normal scores during visual vestibular reflex testing. Five of the 11 subjects had an abnormal OKN bias build up over the course of the run, equal to or actually exceeding the 60 degrees/s target velocity by as much as 14 degrees/s.

Altogether, these results are more suggestive of central nervous system deficits than of peripheral vestibular disfunction.

 

Source: Ash-Bernal R, Wall C 3rd, Komaroff AL, Bell D, Oas JG, Payman RN, Fagioli LR. Vestibular function test anomalies in patients with chronic fatigue syndrome. Acta Otolaryngol. 1995 Jan;115(1):9-17. http://www.ncbi.nlm.nih.gov/pubmed/7762393

 

The impact of catastrophic beliefs on functioning in chronic fatigue syndrome

Abstract:

This study investigated the association between catastrophic beliefs and disability in the context of Chronic fatigue syndrome (CFS). A sample of 282 CFS sufferers were asked about the consequences of pushing themselves beyond their present physical state. Responses were coded into catastrophic or non-catastrophic categories. While not differing on the length of illness or psychological adjustment, subjects demonstrating catastrophic responses evidenced significantly higher levels of fatigue and were more disabled in terms of their ability to work both in their normal occupation and around the house. Catastrophizers also showed greater disability in terms of their sleep and rest, social communication, and recreational activities. The role of catastrophic beliefs and personal perceptions of CFS in maintaining the illness is discussed.

 

Source: Petrie K, Moss-Morris R, Weinman J. The impact of catastrophic beliefs on functioning in chronic fatigue syndrome. J Psychosom Res. 1995 Jan;39(1):31-7. http://www.ncbi.nlm.nih.gov/pubmed/7760301

 

Correlates of somatic causal attributions in primary care patients with fatigue

Abstract:

Researchers in the field of chronic fatigue in tertiary care found that patients’ somatic (e.g. viral) explanations for their condition may lead to chronicity of symptoms. We studied the influence of a somatic attributional bias on outcome and reported symptoms in primary care patients with fatigue.

We compared fatigue scores on a specific scale, and number of presented symptoms, in two groups of primary care patients with ‘functional’ fatigue: 75 with a high score on the somatic subscale of the Fatigue Attribution Scale (S-FAS), and 95 with a low score on the S-FAS. At the index visit, patients with low and high scores on the S-FAS were not different for age, sex, fatigue scores, and levels of depressive symptoms.

Patients with high scores on the S-FAS presented significantly more somatic and psychological symptoms-a total of 36 symptoms for 24 patients (25.3%) in the low-score group, and a total of 52 symptoms for 31 patients (41.3%) in the high-score group.

Forty-two days later, at the follow-up visit, the fatigue scores were similar in both groups. In primary care patients with fatigue not due to somatic illness or major depression, the tendency to attribute fatigue to somatic causes is not associated with a worse outcome, but with a higher number of reported symptoms.

 

Source: Cathébras P, Jacquin L, le Gal M, Fayol C, Bouchou K, Rousset H. Correlates of somatic causal attributions in primary care patients with fatigue. Psychother Psychosom. 1995;63(3-4):174-80. http://www.ncbi.nlm.nih.gov/pubmed/7624463

 

Chronic fatigue syndrome. 1: Etiology and pathogenesis

Abstract:

Chronic fatigue syndrome (CFS) is a disorder of unknown etiology characterized by debilitating fatigue and other somatic and neuropsychiatric symptoms. A range of heterogeneous clinical and laboratory findings have been reported in patients with CFS. Various theories have been proposed to explain the underlying pathophysiologic processes but none has been proved.

Research findings of immunologic dysfunction and neuroendocrine changes suggest the possible dysregulation of interactions between the nervous system and the immune system. Without a clear understanding of its etiopathogenesis, CFS has no definitive treatment.

Management approaches have been necessarily speculative, and they have evolved separately in a number of medical and nonmedical disciplines. The results of several controlled treatment studies have been inconclusive. An accurate case definition identifying homogeneous subtypes of CFS is needed. The integration of medical and psychologic treatment modalities and the use of both biologic and psychologic markers to evaluate treatment response will enhance future treatment strategies.

 

Source: Farrar DJ, Locke SE, Kantrowitz FG. Chronic fatigue syndrome. 1: Etiology and pathogenesis. Behav Med. 1995 Spring;21(1):5-16. http://www.ncbi.nlm.nih.gov/pubmed/7579775

 

Post-hepatitis syndrome revisited

Abstract:

To examine the role of acute hepatitis A and B infection in the aetiology of chronic fatigue syndrome and psychiatric morbidity we studied 40 patients with acute viral hepatitis A or B consecutively admitted to an infectious diseases unit and studied at least 6 months after recovery.

Liver function tests (LFT) had returned to normal in each case. Forty-seven patients with other infectious diseases, of which 12 were presumed viral, admitted immediately after each hepatitis patient during the same period acted as controls. The main outcome measures were scores on a fatigue and muscle pain questionnaire, general health questionnaire (GHQ-12) and supplementary questions.

The hepatitis cases scored significantly higher fatigue scores, GHQ-12 scores and muscle pain scores. Length of time since recovery from illness, age and sex were not confounding factors. Hepatitis cases were also less energetic, had greater weight change, had altered alcohol tolerance, had less exercise tolerance and felt less fit than the control group and compared with their premorbid state.

Hence fatigue is more common after recovery in patients hospitalized for hepatitis A and B up to 30 months post-infection compared with matched controls hospitalized for other infectious diseases. Hepatitis A and B infection is a risk factor for post-infection fatigue, intermittent fatigue, as well as for psychiatric morbidity.

 

Source: Berelowitz GJ, Burgess AP, Thanabalasingham T, Murray-Lyon IM, Wright DJ. Post-hepatitis syndrome revisited. J Viral Hepat. 1995;2(3):133-8. http://www.ncbi.nlm.nih.gov/pubmed/7493307

 

The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group

Abstract:

The complexities of the chronic fatigue syndrome and the methodologic problems associated with its study indicate the need for a comprehensive, systematic, and integrated approach to the evaluation, classification, and study of persons with this condition and other fatiguing illnesses. We propose a conceptual framework and a set of guidelines that provide such an approach. Our guidelines include recommendations for the clinical evaluation of fatigued persons, a revised case definition of the chronic fatigue syndrome, and a strategy for subgrouping fatigued persons in formal investigations.

Comment in:

The chronic fatigue syndrome. [Ann Intern Med. 1995]

The chronic fatigue syndrome. [Ann Intern Med. 1995]

The chronic fatigue syndrome. [Ann Intern Med. 1995]

The chronic fatigue syndrome. [Ann Intern Med. 1995]

 

Source: Fukuda K, Straus SE, Hickie I, Sharpe MC, Dobbins JG, Komaroff A. The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group. Ann Intern Med. 1994 Dec 15;121(12):953-9. http://www.ncbi.nlm.nih.gov/pubmed/7978722